Posts

John Homenuk

Cold, dry weather through weeks end

/0 Comments/by

After the first snowfall of the season on Tuesday, low temperatures fell into the single digits and teens throughout the area by early Wednesday morning. The arctic airmass settling into the area on Wednesday will stick around through the second half of the week, bringing high temperatures down into the upper 20’s and lower 30’s on Thursday. Although there won’t be any harsh biting winds, the snowpack over the interior will make it feel especially cold and will help with radiational cooling during the overnight hours. 850mb temperatures will fall to near -20 C on Thursday afternoon, and temperatures in the teens should be common each morning towards the end of this week.

The calm weather pattern will come as a bit of relief after several days of active weather with a front near the area. Owing to a dominant high pressure over the Northeast US, plenty of sun is likely on each day as we roll towards the weekend. But by the forthcoming weekend, intrigue will again increase as another mid and upper level disturbance tracks from the Central United States towards the Northeast and Mid Atlantic. As a result of this disturbance, a low pressure system is forecast to initially track towards the Ohio Valley. Eventually, a secondary low pressure will redevelop to the east, forced to do so by a strong high pressure to the north and cold air holding firm over New England. The devil is in the details with this system, as the uncertainties suggest potential for a winter weather event, but incredibly low confidence.

NAM model showing low temperatures in the teens on Friday morning.

NAM model showing low temperatures in the teens on Friday morning.

Read more

John Homenuk

Heading into winter, 5 myths about forecast models

/0 Comments/by

As part of our winter forecasting feature this autumn, we’re releasing a few posts with information and tounge-in-cheek opinions about winter and meteorology. The first in the set comes this afternoon, where our forecasters sat down to compile a list of the 5 biggest forecast model myths as we head into winter. You can check them out below, to get a quick primer on what to expect over the next several months.

Read more

John Homenuk

October blocking could hint at winter pattern

/1 Comment/by

Autumn began just a few days ago, but the weather pattern has already adjusted to the fall-like pattern with temperatures falling into the 30’s and 40’s at night. The first cold nights of the year typically come in mid to late September, as the warm and humid days of summer fade. The cooler, more crisp air gives us the first small taste of the cold winter which is only a handful of weeks away. The pattern has begun its seasonal change, and we are beginning to feel the effects of it. Yet, the best hints of what the winter pattern may have in store for us may be hundreds and thousands of miles to our north — over the high latitude/arctic region.

Seasonal forecasting can be a tedious and intricate task for meteorologists. Many times, meteorologists and forecasters alike find themselves drawing upon past events, analogs, and other research for help with predicting the months ahead. This is especially true in the Autumn season, as winter forecasting begins. Meteorologists are about to enter a flurry of forecasting over the next few months (yes, we are somehow enjoying this benign and calm weather right now). So as we look forward to the winter, we can often use the preceding months as indicators of the pattern to come. The pattern itself can often tip its hand, giving us a clue as to what we may be dealing with a few months down the road.

The words “high latitude blocking” likely will instantly bring back memories of some of our stronger storms and more volatile weather patterns in recent memory. The Blizzard of 2010, Hurricane Sandy, the Nor’Easter just a few weeks afterward. They all occurred during episodes of high latitude blocking, with a negative NAO cor North Atlantic Oscillation (for a background and more information on the NAO, click here). Still, high latitude blocking episodes which occur months before these events can often serve as accurate predictors, foreshadowing in a sense, of the upcoming pattern a few months after. A few months ago, we published some research on the blocking pattern during the month of May helping to predict the pattern during the summer months.

For a bit of reference, high latitude blocking refers to blocking ridges which occur in the higher latitudes over Canada and the North Atlantic (background on atmospheric blocking can be found here). These ridges slow down the jet stream/weather pattern. The high latitude blocking over Greenland, the North Atlantic, or Canada during the winter months often leads to the displacement of very cold arctic air over the United States, very often the Northeast US. The more amplified/slower pattern also leads to the potential for large coastal storm systems and has historically featured snowier and colder periods in the Northeast US.

Read more

John Homenuk

North and West of 287: Not just urban legend?

/1 Comment/by

“The best snowfall accumulations should be relegated to areas North and West of 287 in New Jersey.”

For anyone who has been around meteorology, public forecasting, or snowfall forecasting in the media and television over the last 10 or more years, this has been a phrase which will ring many bells and bring back many memories. The media, news outlets, and other forecasters have used the saying of sorts as a way to discern where the higher snowfall totals may occur over the hills and elevated areas of interior Northwest New Jersey. Whether it be via cooler temperatures at the surface, aloft, or a longer duration event in general, it seems that areas North and West of 287 often benefit from their location and elevation in winter storms.

With winter only a few short months away, and the first murmurs beginning in our offices about winter forecasting and seasonal forecasting, the saying brought up a few questions — and the potential for some research. Is “North and West of 287” a generalized phrase, or can it actually be used to differentiate between parts of New Jersey which receive more snow than others? We took a look into the location of I-287 in New Jersey compared to storm specific, seasonal, and long term snowfall averages and found some very surprising results.

Read more